Process of flotation concentration



i 0' very Patented Nov. 6, 1928 UNITED STATES PATENT ..;.O F,FICE.

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PROCESS -IZLOTATION CONCENTRATION.

No Drawing.

of the concentrates is lowered. These min-.

' erals may-otherwise be an undesirable constituent of the concentrates.

One method that has been. disclosed of depressing mica and thereby preventing it from entering the froth is by' the use of starch. We have discovered however that the starch acts in various ways, depending.

upon the condition of the pulp from which not depressing the mica at all but, on the contrary, in certain casesfaiding-it to float. Under'some circumstances, this .is an end greatly desired.

We have discovered the following principles in connection with the use of starch.

1. When thepulp is acid or neutral the addition of starch and the usual flotation 25 oils and reagents will-prevent the mica from enter the froth and prevent the sulphide entering the froth. '2. When the pulp is alkaline, the addition of starch and cyanide and the usual flotation reagents will cause the mica ,to

minerals from sodoing.v

3. When the pulp is alkaline the addition of starch and the usual flotation reagents .will not prevent the-mica from entering thefroth, but if the starch is mixed with acidland added to an alkaline pulp the mica will be prevented from entering thefroth, i. e.,-de pressed.

.When starch andsodium cyanide are added to an alkaline pulp, the sulphides are depressed and the mica floated and the -higher thealkalinity, the less of the other minerals and the moreof the mica that is *When it is desirable to float mica in pref erence to sulphides, the ore must be ground fine enough to free the minerals and mixed with from onexto six parts of water; at this point thepulp should be made distinctly o alkaline, preferably with lime to about .3

u removingthe the froth concentrate is obtained, sometimes;-

' the pul revent the Application filed October 18 192 7. Serial No. 227,048.

amount of cyanide and starch needed depends on the composition of the are.

The more sulphides present the larger the I quantity' of starch. and cyanide needed.-

Two examples to show the effects mentioned above are as follows:

A. A mixed copper mica concentrate in i -a pulp containing .3 lbs/of lime per ton of water was treated with .4 lbs. of starch and 2/10 lbs. cyanide per ton of ore and floated with results as follows:

Per cent Pei cent Cu mica Heads 7.0 i 50.0 Concentrates 1. 9 80. 0 Tails 13.9 10.0

: B. An ore was ground with sufiicient lime and four parts of water to give analkalinit of .2lbs. per ton of water .8 lbs. of stare and .2 lbsof cyanide and .05 lbs. of pine oil per ton of cm were then added to the pulp and .the mica-removed with the froth.

In flotation, it is at times necessary to.

. float the ore in a neutral or acid pulp and with other ores, an alkaline pulp is used to produce the best results. When the pulp is neutral or acid the addition of starch alone is sufiicient to depress the mica; if

acid an starch to depress the mica which greatly increases the cost, 7

Equal weights of starch and sulphuricacid are used as theaddition'agent by us is alkaline it is necessary to add i but we have found the proportion maybe widely varied and still obtain satisfactory results. As examples, an ore containing 1%.; copper and 20% mica was treated as follows The ore was-ground with 3'lbs. of lime per ton and an equal weight of-water, addi-' v tional water was then ad ed to give a dilution of three parts of water to one part of ore, this pulp which showed an alkalinity of .2 lbs. pen-ton was subjected-tea flotation treatment to obtain a .copper "concentrate in the usual manner, 1. e. ;03lbs. of piiie oil and'fllbs. ofxanthate were added and a frothwas rhmoved, this froth contained co per sulphides, iron sulphides, mica and 0t er substances. .The products were as follows: 5

Percent Percent Cu mica rmui a0 4M).

Tails .2

The froth was treated in three ways for comparison as to value of different treatments with starch, the object being' to so treat the pulp that when it was refloated in a flotation machine, a high grade Cu'concentrate couldbe removed with the frbth andthe bulk of the mica would be found in the residue. I I fi .3 lbs. of starch added in a 1% solutionper ton of original mill feedwas added to the froth which was then refloated. This gave a froth assaying 10% Cu niica and tailings assaying 1% Cu and 10% mica. 3/10 lbs. qf starch and .3 lbs. of sulphuric acid per ton of original mill feed were;

mixed into a 1% solution and this solution};

added to the froth which was then refloated This gave a froth assaying 20% Cu 8% mica and tailings assaying .9 percent Cu and mica.

.3 lbs.. of starch added in a 1% solution and 15 lbs. of sulphuric acidper ton of origi-.

' ed, enough a'cid'mustbe used to cause the "water in the pulp to-have a strongly acid reaction, theamouiit needed may var from 1 lb. tolOO lbs.

r ton of ore. nough starch must be u to depress the mica, this depends on the amount presentan'd its tendency to float and may-vary from .01 to 2 or more lbs. per ton of ore and can be dc- .termined by experiment.

ore produced from the same mine on diflerent da'ysirequires difl'erent amounts of reagents.

In a strongly acid pulp by proper additionsof acid and starch, the mica and to a considerable extent the iron pyrites are prevented from floating so that only the more valuable sulphides are floated.

When a solution of starch is mixedwith a small amount of acid or acid substance and this'solutionadded to an alkaline or strong- 1y alkaline pulp, the mica is depressed and the sulphides floated the same as if the pulp was acid or neutral and this occurs in the alkaline pulp in'a much more efiicient manner than without the addition of acid to the starch previous to its addition to the pulp.-

What we claim, is: I 1. In a froth flotation process, the meth-', 0d of separating micaceous and talcky minerals from the concentrates comprising the addition of starch to the ore pulp and make ing the pulp non-alkaline to prevent the said minerals from entering the froth,'\ and then subjecting the ore pulp to froth fldtation.

v 2. In a froth flotation process, the meth- 0d of separating micaceous and talcky minerals in an alkaline pulp, comprising mixing starch with acid and adding it to the alkaline pulp, whereby the mica will be depressed and the sulphides will .enter the froth, and then subjecting froth flotation. I

3. Ina froth flotation process themethod of separating micaceous-and talckymiir' eralsfhomprising' the addition of starch and the ore pulp to acid to an'ore pulp to make it strongly acid,

thereby preventing the micaand iron sulphides. from floatin in the froth and subsequently' floating 0% the other valuable sulphides, and then subjecting the ore pulp to froth flotation.

.4. In a froth flotation process,the meth- There are a great number of. acids, and mass a predetermined reactlon to lit-mus, J

and subjecting said mass to froth flotation.

Intestimony whereof, we afiix' our signaj tures.

r SHE wrN P. LOWE: f

ROBERT PHELAN. 

